The program, known asConficker( http://www.us-cert.gov/cas/techalerts/TA09-088A.html), uses flaws in Windows software to co-opt machines and link them into a virtual computer that can be commanded remotely by its authors. With more than five million of these zombies now under its control government, business and home computers in more than 200 countries this shadowy computer has power that dwarfs that of the worlds largest data centers. Conficker continues to confound the efforts of security experts to trace its origins and determine its purpose.